Chronic ISO injection also caused cardiac hypertrophy, indicated by an increase in global heart size, heart weight to body weight ratio (Fig. 1B and C), cardiomyocyte cross-sectional area, as determined by wheat germ agglutinin (WGA) staining (Fig. 1D and E), and increased hypertrophic marker atrial natriuretic peptide (ANP) mRNA expression (Fig. 1F). This evidence concerns the gene NPPA and cardiac hypertrophy.